In Vivo Ultrasound Exposimetry

Over the past decade, the Department of Obstetrics and Gynecology of the University of Cincinnati College of Medicine (Tariq A. Siddiqi, MD) and the Department of Electrical and Computer Engineering's Bioacoustics Research Laboratory have collaborated in a joint project to ascertain in vivo ultrasound exposure of the human ovary, embryo and fetus during the course of a routine, clinical ultrasound examination. This effort has been driven by the paucity of in vivo data available regarding the actual ultrasonic energy to which the ovum or developing embryo or fetus are exposed after attenuation by the intervening abdominal and uterine walls. We have constructed and developed and tested (and improved upon over the years) an in vivo exposimetry system with customized software (Daft et al., 1989; Daft et al., 1990; Swiney and O'Brien, 1996). We have used our system to determine selected "first-order ultrasonic quantities" i.e. pressure waveform, peak compressional pressure (p_c), peak rarefactional pressure (p_r), as well as selected "second-order ultrasonic quantities" i.e. spatial peak, temporal average intensity (I_SPTA), spatial peak, pulse average intensity (I_SPPA), spatial peak, temporal peak intensity (I_SPTP) during routine reproductive ultrasound examinations (Siddiqi et al., 1991; Siddiqi et al., 1992). We have also reported our results from a series of experiments performed to determine in vivo, tissue-specific ultrasonic attenuation coefficients for each of the tissue layers comprising the anterior abdominal wall, uterus and vagina in a group of healthy, non-pregnant female volunteers using a quantitative, multilayer tissue model (Siddiqi et al., 1995; Siddiqi et al., 1999).

References

C. M. W. Daft, T. A. Siddiqi, D. W. Fitting, R. A. Meyer and W. D. O'Brien, Jr. In-Vivo Fetal Ultrasound Exposimetry. Proceedings of the 1989 IEEE Ultrasonics Symposium, pp. 1053-1056, 1989.

C. M. W. Daft, T. A. Siddiqi, D. W. Fitting, R. A. Meyer and W. D. O'Brien, Jr. In-Vivo Fetal Exposimetry. IEEE Transaction on Ultrasonics, Ferroelectrics, and Frequency Control 37, 500-505, 1990.

T. A. Siddiqi, W. D. O'Brien, Jr., R. A. Meyer, J. M. Sullivan and M. Miodovnik. In Situ Exposimetry: The Ovarian Ultrasound Examination. Ultrasound in Medicine and Biology, 17, 257-263, 1991.

T. A. Siddiqi, W. D. O'Brien, Jr., R. A. Meyer, J. M. Sullivan and M. Miodovnik. Human In Situ Dosimetry: Differential Insertion Loss during Passage through Abdominal Wall and Myometrium. Ultrasound in Medicine and Biology, 18, 681-689, 1992.

T. A. Siddiqi, W. D. O'Brien, Jr., R. A. Meyer, J. M. Sullivan, and M. Miodovnik. In Situ Human Obstetrical Ultrasound Exposimetry: Estimates of Derating Factors for each of Three Different Tissus Models. Ultrasound in Medicine and Biology, 21, 379-391, 1995.

D. Swiney and W. D. O'Brien, Jr. Human Fetal Diagnostic Ultrasound Exposimetry System. Proceedings of the 1996 IEEE Ultrasonics Symposium, pp 1167-1169, 1996.

T. A. Siddiqi, M. Miodovnik , R. A. Meyer and W. D. O'Brien, Jr. I. In Vivo Ultrasound Exposimetry: Human Tissue-Specific Attenuation Coefficients in the Gynecologic Examination. American Journal of Obstetrics and Gynecology, 180, 866-874, 1999.